Re: Can lower layer tell there's connectivity? (Was: Re: Newissue 16: No packets from other end?)

> (2) Ensuring that a given address really is the same
>      node. When probing for the correctness of a claimed
>      address, we may want to ensure that its indeed the
>      same IKEv2 node at this address.
>
>      It seems that the only way to do this is an IKEv2
>      message. But note that we are talking about address
>      update, not failure recovery here. So failure recovery
>      might still work using only IP layer connectivity
>      tests.
>

I assume that could only be determined by authentication, so an IKEv2
message with proper ESP Auth header (or AH if that will be supported by
MOBIKE).

> (3) What current lower layers are able to tell to MOBIKE.
>      This is what I have been saying, that as far as I know,
>      current lower layer support in IPv6, DNA, DHC, etc.
>      only provides support for the discovery of available
>      addresses and locally operational addresses. Not the
>      discovery operational address pairs.
>
>      I'm not saying that it wouldn't be possible to develop
>      one, just that one doesn't exist now. But I could be
>      missing something, I'm sure you guys will tell me what...
>

Base reachability is determined by 2461 NUD (modulo the DNA work which is
still underway). I think RFC 2461 says that NUD can and should be
supplemented by upper layer reachability information. So from that
standpoint, MOBIKE could be considered an "upper layer" protocol that could
contribute to the NUD decision. The issue, as I see it,  is whether MOBIKE
should make the decision or not.

            jak